Tub frame



FIG. 1 is a top and side perspective view of a tub frame showing our new design in full lines, and environmental association matter shown in broken lines and forms no part of the claimed design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a side elevational view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a tub frame, as shown and described. 